VIENNA - Interventional treatments for arteriosclerosis of the lower extremities, including stenting and balloon angioplasty, have produced excellent results, at least in the short term. But complications from the procedures and continuing high restenosis rates have spurred the drive for better solutions. Among the newer techniques, high-speed rotational ablation procedures are initially successful but deliver poor results at follow-up, according to German researchers at the European Congress of Radiology's March 7 scientific sessions.
Dr. Thomas Jahnke of the department of radiology at Kiel University in Germany presented the results of his team's study on the mid-term effectiveness and patency rates of infrapopliteal percutaneous transluminal rotational ablation (PTRA) in the treatment of arterial occlusive disease.
Jahnke said PTRA offered several theoretical advantages over balloon angioplasty, including its ability to "cut through inelastic plaque material with minimal wall stretching" or other arterial damage. In addition, the procedure pulverizes displaced plaque into microparticles, thus minimizing the possibility of its blocking other vessels. In contrast, traditional balloon angioplasty produces deep splits in the vessel wall, he said, and releases larger plaque debris into the coronary distal circulation.
Jahnke also said there was little trial data on use of the high-speed rotational ablation for indications similar to his patients' -- only a small study done in 1994 that showed poor results with the technique.
Over 18 months, the doctors at Kiel treated 19 lesions in 15 patients (8 female, 7 male) with a mean age of 67. All of the patients had severe and lifestyle-limiting arterial claudication, with pain at rest, and ischemic skin changes. Most also had major risk factors such as smoking or diabetes, and a majority presented with stenoses of the anterior tibial artery. None had undergone stent placement or had previous thromboses.
The narrowed arteries were first measured with DSA and electronic calipers to determine the correct size of the burr head (from 1.5 to 4.5 mm) for a flexible rotating catheter-based device, the Rotablator, manufactured by Heart Technology of Bellvue, WA. The device has a burr head covered with microscopic diamond particles that do the cutting, and rotates at 160-180 rpm.
In the procedure, a .009-inch guide wire was inserted percutaneously into the artery, followed by the device, which was activated and moved back and forth in the artery several times until there was no further resistance to the movement. Follow-up occurred at 1, 3, and 6 months with Doppler sonography, and also with angiography at 6 months.
The initial results were excellent. Rotational angioplasty was successful in 18 of 19 procedures (94%). In these patients, treadmill exercises and mean Doppler-ankle-brachial index (ABI) measurements showed significant improvement of blood flow in the recanalized vessels, from approximately 0.6 before the procedure to .88 immediately following it. Doppler analysis yielded similar results at 1 month, however by 3 months the ABI had dropped to approximately .72, and to .7 by six months.
While 7 patients were lost to follow-up examinations (including 2 in deaths apparently unrelated to the procedure), the six-month follow-up on the remaining 12 patients showed 6 high-grade restenoses, and 5 total occlusions, for an overall restenosis rate of 91%. Only one patient's treated artery remained patent at six months.
There were complications as well, including disembolization in one patient that was successfully treated by ablation, an arterial spasm in one patient, and arterial rupture in one patient caused by a "burr head that was not tuned correctly in relation to the treated artery," Jahnke said.
"Due to these poor results we decided to terminate the study, although we had initially intended it as a long-term trial," Jahnke said. "So in conclusion, we do not recommend rotational ablation as a primary treatment option for infrapopliteal occlusive disease," especially considering the cost of the procedure, about six times that of balloon angioplasty, he said.
An audience member questioned the use of the experimental technique for the condition indicated, as well as its use as the sole method of recanalization. Jahnke answered that the device was approved for the indication.
Session chair Dr. L. Horvath cautioned that it was important to account for the underlying disease in assessing the results.
"I'm pretty sure that if we treat local changes in arteriosclerosis we are not treating the disease," he said. "We have no right to believe that the disease itself will not progress." He said the best way to treat the disease was to stop the cause. "Stop smoking, treat the diabetes," he said.
By Eric Barnes
Auntminnie.com staff writer
March 7, 2000
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